smartmontools: add init script

Add init script smartd for smartmontools. Thought smartmontools provides
init script itself, but it checks distribution version that is not usable
for oe.

So add an init script for smartmontools which removes distribution
version check.

Signed-off-by: Kai Kang <kai.kang@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>